1. Field of the Invention
This invention relates to a printer interface device for a computer, more particularly to a dual purpose printer interface device capable of connecting a printer and a joystick to a portable host computer.
2. Description of the Related Art
Presently, a conventional portable host computer lacks a joystick interface device owing to insufficient space of the conventional portable host computer.
Referring to FIG. 1, a conventional printer interface device is shown to comprise a printer data register 11, a printer control register 12, a printer status register 13, an address decoder and read/write controller 14 and a bus driving means 15. The data register 11 has eight data transmission lines (P0-P7). The control register 12 has four control lines (STB,AFD,INIT,SLIN). The status register 13 has five status lines (ACK,BUSY,PE,SLCT,ERROR). The data, control and status registers 11,12 and 13 are connected electrically to a printer connector (A) which has twenty-five contacts. The printer connector (A) is to be connected to a printer (not shown). The conventional printer interface device is connected electrically to the address bus (SA0-SA9) of the conventional host computer (C) via the address decoder and read/write controller 14 and to the data bus (D0-D7) of the host computer (C) via the bus driving means 15. Operation of the controller 14 is controlled by an input/output read enabling signal (IOR) and an input/output write enabling signal (IOW) from the host computer (C).
Since the conventional portable host computer has an insufficient space for accommodating a conventional joystick interface device, and since the conventional printer interface device cannot function as a joystick interface device, there is a need to provide a dual purpose printer interface device which is capable of connecting a printer and a joystick to a portable host computer.